The aforementioned compound represented by formula (VI): ##STR2## (wherein n is an integer of 2 to 5) has been produced via a multi-step production process using ethyl acetoacetate as the starting material (JP-A-2-231475). In addition, an optically active form of this compound is obtained by preparing a diastereomer compound having an optically active protecting group, isolating it using a preparative high performance liquid chromatography and then removing the protecting group (JP-A-3-95176). However, such a method requires complex handling, hence leaving room for the improvement as an industrial production process.
It is accordingly an object of the present invention to provide a process for the inexpensive, short-step and industrially advantageous production of nitrogen-containing heterocyclic compounds having a spiro-cyclic structure, particularly an optically active azaspiro2.4!heptane derivative.